Wen Li Zhang

Process Optimization and Application of Supported Nano-Photocatalytic Materials

Melt Phase-splitting[1] method was a new one of preparing supported nano-photocatalytic materials.The nano TiO2 prepared loaded to the porous glass carrier. In this study,the technology of preparing nano TiO2 by melt phase-splitting method was Optimization, also doing doping modifcation on them. Using nano TiO2 photocatalyst to do photocatalytic degradation test on formaldehyde.The result had shown that: the degradation efficiency of the catalyst containing ZnO was higher than that free of ZnO. The rate of degradation of formaldehyde of the catalyst free of ZnO could reached 58.7% in 8 hours, but that of the catalyst containing was only 53.3%. Using fluorescent lamps as the light source,the photocatalytic efficiency of the catalyst free of ZnO could reached 43.2%.

Study on the Photocatalytic Properties with Different Ratio Films of ZnO:Fe2O3

The nanocomposite films with different ZnO:Fe2O3 ratio was prepared by Sol-Gel method on slides glass, Its structure performance was characterized by XRD, SEM, and the photocatalytic performance of different ZnO: Fe2O3 ratio films was investigated. The results showed that: the three layers film that with Zn: Fe ratio was 1:2, had the best photocatalytic effect.

Interface Reactions of Joining Al2O3 Ceramics by Microwave Method

Nanometer Si powders were used as interlayer materials, which were expected to be microwave heated rapidly and reacted with the surface of Al2O3 ceramics to form the low eutectoid compound. The phenomena of element migration of joint samples were investigated by energy dispersive spectroscopy (EDS) and the interface phase transition was analyzed by X-ray diffraction (XRD). The results indicated that the low eutectoid compound of the joint interface wetted and penetrated to the ceramic surface. The variation of micro-hardness at the interface across the parent material was measured by micro-hardness instrument and the interfacial microstructure and the fracture surface were investigated by scanning electron microscopy (SEM).

Microwave Joining Alumina Ceramics Using Al-Si Alloy Powders at Low Temperature

Alumina composites were joined in air by microwave heating, along with Al-Si alloy powder as the interlayer. The interfacial microstructure and the fracture surface were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Element and phase components of the interlayer were analyzed by X-ray diffraction (XRD). Experimental results clearly indicated that microwave heating method effectively hampered the oxidation of the interlayer and indirectly promoted adhesion. The molten Al-Si alloy wetted and penetrated to the 95-Al2O3 ceramics surface, which formed the well joining interface.

The Study of TiO2 Whiskers Prepared by Melt Phase-Splitting Method and their Photocatalytic Properties

This paper studied the preparation of TiO2 whisker with melt phase-splitting method, which used tataniferous blast-furnance as the main raw materrial. XRD and SEM were used to research the phase and morphology of the sample, and by the same time, the photocatalytic properties of TiO2 crystal-beards was tested.The result have shown:the size of TiO2 crystal-beards was sub-micron rank, the crystal type wasβ-TiO2 of orthorhombic high-pressure phase. The generation of TiO2 crystal-beards were effected mainly by the content of Na2O and TiO2, and the heat treatment temperature. The sample had certain photocatalytic properties and the highest photocatalytic efficiency was 56%.

The Joining of Oxide Ceramics with Quartz Fiber by Interlayer

The joining of ZrO2 ceramic and quartz fiber was realized by glass interlayer heat-treatment at 800 °C for 1h. Using the low-temperature liquid reaction of B2O3-SiO2 and B2O3-ZrO2 and the properties change of borosilicate glass, the two kind materials of different thermal expansion coefficients achieved joint by B2O3 as the interlayer material. Through observing the micro-morphology of joint samples at different heat-treatment temperature, and combining with the fibers’ high temperature properties, the optimum joining temperature was investigated. According to the phase diagrams of B2O3-SiO2 and B2O3-ZrO2 and SEM results of joints region, the joint mechanism of density ceramics and fiber weaves was discussed in detail.

A Novel Material Preparation of Density Ceramics and Fibre Joining

The joining materials of density ceramics and woven fibres would be potential value as sealing parts for thermal protection system application in aerospace field. Based on ZrO2-Al2O3-SiO2 phase diagram, the ceramics matrix and interlayer compositions were designed. Using the absorber-microwaves properties of Al-Si alloy, the joining of ZTM ceramics and fibre materials with interlayer was achieved by microwave hybrid heating method. The experiment results indicated that the interlayer ingredients were mullite, zirconia and alumina after microwave sintering. The strength of joint specimens was related with the interlayer compositions and the specimen preserved elasticity property according to the test result of universal testing machine. The joint mechanism of interlayer by microwave sintering was discussed in this paper.

Study on the Influence Factors of ZnFe2O4 and TiO2 Composite Films Photoelectrocatalytic Properties

The ZnFe2O4 and TiO2 nanocomposite films was prepared by Sol-Gel method on conductive glass, and the influence factors of it’s photoelectrocatalytic performence such as the film layer, pole and voltage was investigated. The results indicated that: the photocatalytic effects of composite films with ZnFe2O4+ TiO2+ ZnFe2O4 was the best. The decomposing ratio of methyl orange with the photoelectrocatalysis of composite films at voltage 0.2-6V all increased unstably.At the same time, the distance from films to pole plank also had the effects on the photocatalytic activities of the films.